172 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// REQUIRES: std-at-least-c++2610 11// <numeric>12 13// template<class T>14// constexpr T add_sat(T x, T y) noexcept; // freestanding15 16#include <cassert>17#include <concepts>18#include <limits>19#include <numeric>20 21#include "test_macros.h"22 23template <typename IntegerT>24constexpr bool test_signed() {25 constexpr auto minVal = std::numeric_limits<IntegerT>::min();26 constexpr auto maxVal = std::numeric_limits<IntegerT>::max();27 28 std::same_as<IntegerT> decltype(auto) _ = std::add_sat(minVal, maxVal);29 30 static_assert(noexcept(std::add_sat(minVal, maxVal)));31 32 // clang-format off33 34 // Limit values (-1, 0, 1, min, max)35 36 assert(std::add_sat(IntegerT{-1}, IntegerT{-1}) == IntegerT{-2});37 assert(std::add_sat(IntegerT{-1}, IntegerT{ 0}) == IntegerT{-1});38 assert(std::add_sat(IntegerT{-1}, IntegerT{ 1}) == IntegerT{ 0});39 assert(std::add_sat(IntegerT{-1}, minVal) == minVal); // saturated40 assert(std::add_sat(IntegerT{-1}, maxVal) == IntegerT{-1} + maxVal);41 42 assert(std::add_sat(IntegerT{ 0}, IntegerT{-1}) == IntegerT{-1});43 assert(std::add_sat(IntegerT{ 0}, IntegerT{ 0}) == IntegerT{ 0});44 assert(std::add_sat(IntegerT{ 0}, IntegerT{ 1}) == IntegerT{ 1});45 assert(std::add_sat(IntegerT{ 0}, minVal) == minVal);46 assert(std::add_sat(IntegerT{ 0}, maxVal) == maxVal);47 48 assert(std::add_sat(IntegerT{ 1}, IntegerT{-1}) == IntegerT{ 0});49 assert(std::add_sat(IntegerT{ 1}, IntegerT{ 0}) == IntegerT{ 1});50 assert(std::add_sat(IntegerT{ 1}, IntegerT{ 1}) == IntegerT{ 2});51 assert(std::add_sat(IntegerT{ 1}, minVal) == IntegerT{ 1} + minVal);52 assert(std::add_sat(IntegerT{ 1}, maxVal) == maxVal); // saturated53 54 assert(std::add_sat( minVal, IntegerT{-1}) == minVal); // saturated55 assert(std::add_sat( minVal, IntegerT{ 0}) == minVal);56 assert(std::add_sat( minVal, IntegerT{ 1}) == minVal + IntegerT{ 1});57 assert(std::add_sat( minVal, minVal) == minVal); // saturated58 assert(std::add_sat( minVal, maxVal) == IntegerT{-1});59 60 assert(std::add_sat( maxVal, IntegerT{-1}) == maxVal + IntegerT{-1});61 assert(std::add_sat( maxVal, IntegerT{ 0}) == maxVal);62 assert(std::add_sat( maxVal, IntegerT{ 1}) == maxVal); // saturated63 assert(std::add_sat( maxVal, minVal) == IntegerT{-1});64 assert(std::add_sat( maxVal, maxVal) == maxVal); // saturated65 66 // No saturation (no limit values)67 68 assert(std::add_sat(IntegerT{-27}, IntegerT{28})== IntegerT{ 1});69 assert(std::add_sat(IntegerT{ 27}, IntegerT{28})== IntegerT{55});70 {71 constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};72 constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};73 assert(std::add_sat(x, y) == maxVal);74 }75 76 // Saturation (no limit values)77 78 {79 constexpr IntegerT x = minVal / IntegerT{2} + IntegerT{-27};80 constexpr IntegerT y = minVal / IntegerT{2} + IntegerT{-28};81 assert(std::add_sat(x, y) == minVal); // saturated82 }83 {84 constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};85 constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};86 assert(std::add_sat(x, y) == maxVal); // saturated87 }88 89 // clang-format on90 91 return true;92}93 94template <typename IntegerT>95constexpr bool test_unsigned() {96 constexpr auto minVal = std::numeric_limits<IntegerT>::min();97 constexpr auto maxVal = std::numeric_limits<IntegerT>::max();98 99 std::same_as<IntegerT> decltype(auto) _ = std::add_sat(minVal, maxVal);100 101 static_assert(noexcept(std::add_sat(minVal, maxVal)));102 103 // clang-format off104 105 // Litmit values (0, 1, min, max)106 107 assert(std::add_sat(IntegerT{0}, IntegerT{0}) == IntegerT{0});108 assert(std::add_sat(IntegerT{0}, IntegerT{1}) == IntegerT{1});109 assert(std::add_sat(IntegerT{0}, minVal) == IntegerT{0});110 assert(std::add_sat(IntegerT{0}, maxVal) == maxVal);111 assert(std::add_sat(IntegerT{1}, IntegerT{0}) == IntegerT{1});112 assert(std::add_sat(IntegerT{1}, IntegerT{1}) == IntegerT{2});113 assert(std::add_sat(IntegerT{1}, minVal) == IntegerT{1});114 assert(std::add_sat(IntegerT{1}, maxVal) == maxVal); // saturated115 assert(std::add_sat( minVal, IntegerT{0}) == IntegerT{0});116 assert(std::add_sat( minVal, IntegerT{1}) == IntegerT{1});117 assert(std::add_sat( minVal, minVal) == minVal);118 assert(std::add_sat( minVal, maxVal) == maxVal);119 assert(std::add_sat( maxVal, IntegerT{0}) == maxVal);120 assert(std::add_sat( maxVal, IntegerT{1}) == maxVal); // saturated121 assert(std::add_sat( maxVal, minVal) == maxVal);122 assert(std::add_sat( maxVal, maxVal) == maxVal); // saturated123 124 // No saturation (no limit values)125 126 assert(std::add_sat(IntegerT{27}, IntegerT{28}) == IntegerT{55});127 128 // Saturation (no limit values)129 130 {131 constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};132 constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};133 assert(std::add_sat( x, y) == maxVal); // saturated134 assert(std::add_sat( x, maxVal) == maxVal); // saturated135 assert(std::add_sat(maxVal, y) == maxVal); // saturated136 }137 138 // clang-format on139 140 return true;141}142 143constexpr bool test() {144 // Signed145 test_signed<signed char>();146 test_signed<short int>();147 test_signed<int>();148 test_signed<long int>();149 test_signed<long long int>();150#ifndef TEST_HAS_NO_INT128151 test_signed<__int128_t>();152#endif153 // Unsigned154 test_unsigned<unsigned char>();155 test_unsigned<unsigned short int>();156 test_unsigned<unsigned int>();157 test_unsigned<unsigned long int>();158 test_unsigned<unsigned long long int>();159#ifndef TEST_HAS_NO_INT128160 test_unsigned<__uint128_t>();161#endif162 163 return true;164}165 166int main(int, char**) {167 test();168 static_assert(test());169 170 return 0;171}172